Rotate UVs 90 Degrees Shortcut
I use TexTools addon. It was 2.79 but someone ported it to 2.8 and it works pretty well



as you can see it has a -90 and +90 which you can assign a shortcut key to if required

here is the download

https://github.com/SavMartin/TexTools-Blender/releases/download/TexTools_2.80/textools.zip